I need to generate a checksum (64 bits) and have never done so before. First time for everything. In the Camel book, 2nd revision, page 237, there is sample code to generate a 32-bit checksum, (i think):

$checksum = unpack("%32C*", $foo) % 32767;
[download]

32767 is really just 2^(16-1)-1, but what is up with the first argument to unpack: "%32C*"? The 32C makes sense to me, but the % and the * elude me.

Second question is, will the following generate a 64-bit checksum:

$checksum = unpack("%64C*", $foo) %  2**(64-1)-1
[download]

? Also, if anybody knows of any good resources on generating checksums, please post them. Thanks in advance.

in the meantime, looks like a new Q&A is in order - How do I generate an N-bit checksum?

Jeff

R-R-R--R-R-R--R-R-R--R-R-R--R-R-R--
L-L--L-L--L-L--L-L--L-L--L-L--L-L--

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